复合生物膜系统的营养物去除效应及生物膜特征

Nutrient Removal and Microbial Community Structure in Hybrid Biofilm Reactor

为明确复合生物膜系统(HBR)中悬浮污泥和生物膜对脱氮除磷的贡献,对比研究了序批式活性污泥系统(SBR)和HBR对营养物的去除特性。在0.8 kgCOD/(m3.d)的负荷下,HBR具有较好的脱氮除磷效果,对NH3-N、TN和TP的去除率分别可达96%、92%和94%,高于对照的SBR工艺。在HBR系统中,悬浮污泥主要起到硝化作用,生物膜主要起到反硝化和除磷作用。生物膜主要由胞外聚合物(EPS)、细胞簇丛、孔洞和通道组成。生物膜生长状态良好,丝状菌结构支架较明显,大量的球菌、杆菌穿插其中,密集地粘附于填料之上。FISH检测结果表明,生物膜上存在大量的氨氧化菌和聚磷菌,两者分别占总菌数量的9.4%和13.7%,提高了HBR对营养物的去除效果。

The characteristics of nutrient removal in hybrid biofilm reactor （HBR） and sequencing batch reactor （SBR） were compared to determine the contribution of suspended sludge and biofilm in HBR to nitrogen and phosphorus removal. Under 0.8 kgCOD/（ m^3· d）, the HBR had higher nitrogen and phosphorus removal efficiency. The removal rates of NH3 - N, TN and TP were 96%, 92% and 94% respectively, which were higher than those in SBR. In the HBR, suspended sludge played an im- portant role in nitrification and biofilm played an important role in denitrification and phosphorus removal. The biofilm was mainly composed of extracellar polymeric substances （EPS）, cell clusters, holes and channels. The biofilm grew in good condition, a large number of cocci and bacilli interspersed among structural frame of filamentous bacteria adhered to the surface of suspended carriers. FISH results showed that many phosphate-accumulating bacteria （PAO） and ammonia-oxidizing bacteria （AOB） existed on the surface of biofilm. The percentages of AOB and PAO amongst total microorganisms were 9.4% and 13.7%, respectively. The bacteria improved the removal efficiency of nutrients in HBR.